RESUMO
BACKGROUND: IL-13 has been implicated in the pathogenesis of asthma and in the regulation of IgE synthesis in humans. Single nucleotide polymorphisms (SNPs) in the IL-13 gene have been associated with asthma and total serum IgE level in Caucasian populations. OBJECTIVE: To test for genetic association between an SNP in exon 4 of the IL-13 gene (IL-13 + 2044 or Arg130Gln) and total serum IgE level and asthma-related phenotypes in a population with high prevalence of asthma living in Costa Rica. METHODS: Family-based association study. RESULTS: Among 83 Costa Rican school children with asthma and their parents (249 individuals), there was no evidence of linkage disequilibrium between the IL-13 + 2044 SNP and any of the outcomes of interest (total serum IgE level on a logarithmic scale, number of positive skin tests to aeroallergens, and asthma). These results were not significantly changed after adjustment for age and gender. CONCLUSIONS: No significant evidence of linkage disequilibrium between an SNP in exon 4 of the IL-13 gene and total serum IgE level, sensitization to allergens or asthma was found in a family-based association study in Costa Rica.
Assuntos
Imunoglobulina E/sangue , Imunoglobulina E/genética , Interleucina-13/genética , Núcleo Familiar , Polimorfismo Genético/genética , Alérgenos/genética , Alérgenos/imunologia , Asma/genética , Asma/imunologia , Criança , Proteção da Criança , Costa Rica/epidemiologia , Saúde da Família , Feminino , Frequência do Gene , Genótipo , Humanos , Imunoglobulina E/imunologia , Interleucina-13/imunologia , Desequilíbrio de Ligação/genética , Desequilíbrio de Ligação/imunologia , Masculino , Polimorfismo Genético/imunologia , Testes CutâneosRESUMO
The behavior of hepatitis A virus (HAV) infection among 980 members of 230 families in two rural districts of Costa Rica was studied prospectively from the recognition of the index case. The initial prevalence of detectable antibody (anti-HAV) ranged from 26.2% in children to 71.4% in adults. The ratio of index to household-associated infections was significantly higher among children than among adolescents and adults, indicating that children were most often responsible for the HAV introduction. The rates of household-associated cases among susceptible contacts were 70-83%; the final prevalences of anti-HAV were 90-95%. Neither index showed significant differences related to age. The ratio of clinical to silent infections in household-associated cases was uniformly 1.8:1 among children and adolescents; among adults, almost all associated infections were silent. Beginning with the 5-9-year age group, however, an immunoglobulin M response was absent in a progressively larger proportion of inapparent infections, strongly suggesting restimulation of specific immunoglobulin G antibodies by reinfection.
Assuntos
Hepatite A/genética , Adolescente , Adulto , Fatores Etários , Anticorpos Antivirais/imunologia , Criança , Pré-Escolar , Costa Rica , Métodos Epidemiológicos , Hepatite A/epidemiologia , Hepatite A/imunologia , Humanos , Imunoglobulina M/imunologia , Lactente , Estudos ProspectivosRESUMO
We examined the clinical significance of hepatitis Be antigenemia in 36 HBsAg positive pediatric dialysis and renal transplant patients. One hundred twenty-seven sera were tested for HBeAg and anti-HBe. Seventy-three sera (57%) from 29 patients (81%) contained HBeAg. The presence of HBeAg was associated with an increased titer of HBsAg (P < 0.005) and with the presence of the HBsAg carrier state (P < 0.001). HBeAg was found in 40% of specimens taken from dialysis patients, and in 70% of specimens from transplant patients (P < 0.001). No serum contained anti-HBe, although 28 of 29 sera (97%) tested had antibody to HBcAg. No association was found between the presence of HBeAg and serum aminoleucine transferase levels or the histologic evidence of chronic active hepatitis. Fifteen HBeAg negative sera from patients persistently positive for HBsAg were tested for HBV-specific DNA polymerase activity; 7 (47%) had significant activity. Since both HBeAg and DNA p are indicators of infectivity, many HBeAg negative sera from immunosuppressed HBsAg carriers may be infectious.
Assuntos
Antígenos da Hepatite B/análise , Antígenos E da Hepatite B/análise , Hepatite B/imunologia , Transplante de Rim , Diálise Renal , Adolescente , Adulto , Criança , Pré-Escolar , DNA Polimerase Dirigida por DNA/metabolismo , Feminino , Anticorpos Anti-Hepatite B/análise , Antígenos do Núcleo do Vírus da Hepatite B/análise , Antígenos de Superfície da Hepatite B/análise , Humanos , Lactente , Nefropatias/imunologia , Masculino , Transplante HomólogoRESUMO
With the finding of HBV and HAV, it is possible at the present time to recognize according to its etiology three types of viral hepatitis: type A, Type B and type non-A-non-B. In this paper we have proved that a low socioeconomic status plays a very important role in the spreading of this disease. In a community with a low socioeconomic status, of forty children attending the fourth grade of a primary school, 97 percent were found to have anti-HA: while in a similar group of children with a higher socioeconomic background, we found only 40 per cent of positive cases. A positive sero convertion to anti-HA was found in 90 per cent of the 73 children with acute hepatitis; the remaining 10 per cent were non-A-non-B. A group of 61 children admitted to the L. Calvo Mackenna Children's Hospital with acute or chronic non hepatic disease were studied for anti-HA. We found 77% positive cases in the group of infants under 4 months old; in older infants, a low incidence of anti-HA was observed, but a notorious increase of positive cases was seen after the age of two years, reaching 100 percent of positive cases in children above four years of age. In ten patients studied with prolonged hepatitis, five of them could be possibly classified as having a non-A-non-B hepatitis.